Clamp tight switch



July 4, i950 o. JENSEN CLAMP TIGHT SWITCH 5 sllees--Sheraty l Filed April 30, 1946 mw T. NW Ee V mm O ATTORNEYS July 4, 1950 0, JENSEN 2,513,649

CLAMP TIGHT SWITCH Filed April 50, 1946 3 Sheets-Sheet 2 INVENTOR. Orfo denser) A TTUR NEYJ July 4, 1950 o. JENSEN 2,513,649

CLAMP TIGHT SWITCH Filed Apzil 50, 1946 3 Sheets-Sheet 3 INVENTOR. ONO denser) ATTORNEYS Patented July 4, 1950 f f., 1

Otto Jensen, Malvern, Circuit Breaker Com Pa., assigner to I. T. E.

pany, Philadelphia, Pa., a

corporation of Pennsylvania Application April 30, 1946, Serial No. 665,947

Claims. l

My present invention relates to switchgear and more particularly to double throw switchgear arranged to engage the movable contact with the stationary contacts in a tight clamping arrangement in each position of the double throw switch.

l-Ieretofore in switchgear of the knife switch type, it has been customary to provide a clamping arrangement for interengaging the movable element of the knife switch with the stationary contact. A portion of the closing movement of the switch was used to bring the movable contact or blade up into registry was the stationary contact and the remaining movement of the switch handle performedI the clamping action. This type of clamping action is shown in the Scott Patent 2,246,672, assigned to the assignee of the present invention.

However, the problem becomes more complex in double throw switches where the movable contact blade has a neutral position as well as two separate contacting positions 180o apart.

Various means have been attempted to provide for adequate clamping pressure at both contacting positions of the knife blade but these have resulted either in extremely complex duplicate clamping mechanisms or in having a clamped contact arrangement at one position only with the other position being subjected to only light clamping engagement.

In general, my invention contemplates the utilization of a single right hand thread screw member which will be actuated when the switch is closed in either dir-ection to clamp the switch blades tightlyl across the contacts, although it will be understood that a left handed screw may be employed, if desired.

More specifically, my invention contemplates a clamp tight switch arrangement in which the movable contact carrying arm is mounted on a screw member threaded at both ends. The switch is a two-blade single pole switch and is so a-rranged that when the contact is moved into either of its contact engaging positions, it is clamped against the stationary contact members.

When the contact member is in one of its contact engaging positions, the screw member is rotated clockwise. Clockwise rotation causes the screw to react on a nut at one end as at the left end through the nut to compress the contact member against the stationary contact, the direction of the clamping force being opposite to the direction of axial movement of thescrew member.

The same clockwise rotation of the screw member causes the other end of the screw to directly compress the movable contact against the opposite side of the fixed contact, the force being in the same direction as the axial movement of the screw member.

(Cl. ZOO-70) When the movable contact is moved to its opposite pole, the screw member is rotated counterclockwise. Counterclockwise rotation of the screw member causes the screw to rotate on the nut located on the opposite side from the above described nut, namely, on the right hand and through this other nut to compress the movable contact against the fixed contact in a direction opposite to the a-Xial movement of the screw member. The same counterclockwise rotation causes the other end of the screw member to directly compress the movable contact against the Xed contact into the same direction as the axial movement screw member.

Summarzing the above, a screw member arrangement is thus provided which clamps a movable contact against one of its two pole terminals when the movable contact is rotated clockwise and clamps it against the other of its two pole terminals when the movable contact is moved into opposite counterclockwise direction.

Accordingly a primary object of my present invention is to provide a simple clamping mechanism primarily for a double throw knife type switch wherein a single clamping member and single operating means therefor is eiective to create proper contact engaging clamping pressure at both contact closing positions of the knife'switch.

Another object of the present invention is the provision of clamping means for a double throw knife type switch wherein the clamping means is released when the switch blade is in neutral intermediate position but wherein the clamp is operated to engaged position on movement of the switch handle in either direction from the neutral.

The foregoing and many other objects of my invention will become apparent in the following description and drawings in which Figure l is a side View showing the general operation of my novel clamping means for a double throw knife type switch.

Figure 2 is a bottom view of the switch handle taken from line 2-2 of Figure l.

Figure 3 is an end View of the latch means for the switch handle taken from line 3'-3 of Figure l.

Figure 4 is a front view l in the upper connected position with the handle assembly partly broken away.

Figure 5 is a cross-sectional View taken from line 5-5 of Figure l and showing the arrangement f of the clamping mechanism when the switch 'is closed against the upper stationary contact.

f Figure 6 is a view corresponding to that of Figure 5 showing the arrangement of the clamping mechanism when the switch is open with the switch handle in neutral position.

of the switch of Figure Figure 7 is a view corresponding to that of Figure showing the arrangement of the clamping mechanism with the switch closed and in engagement with the bottom switch contact.

Referring now to Figure 1, my novel doublethrow knife type switch I6 is mounted on an irisulating panel II which carries the upper 'stationary contact terminal I2 and the lower stationary contact I3. Contact terminals I2 and I3 are supplied with special conductive alloy buttons I4, I4 and are part of theconductive back connection studs I5, I6 which pass through appropriate openings I1, I8 respectively in the insulating panel II. The movable contact assembly is rotatably mounted on the central terminal block 26 which in turn is conductively secured to the back connecti'on stud 21 which passes through opening 2'8 in insulating panel II. Terminal block 26 carries the pair of upper link members 30 and the pair of lower link members 3| pivotally secured thereto at pivots 33 and 34, respectively. The opposite ends of the pair of arms 30 are pivotally secured by the rivets 3'5 to the clamp plate 15 hereinafter described. The lower arms 3"I are similarly pivotally secured by the rivets 36 to the clamping plate 15.

My novel vdevice is so arranged, as hereinafter described, that the contact plates or blades 40, 40 are bridged and clamped across terminal 26 and contact Vterminal I2 in the upper closed position of the s witch, and across terminal 26 and contact terminal I3 in the lower closed 'position of the switch; but that in any intermediate position, the plates or blades 40, 4B' will be spaced apart sufiiciently so that they may readily move from one contact bridging position to the other.

In operation, when the switch is in the up position of Figure 1, the initial downward -movement of handle 4I will release the clamp which holds the contact plates 40, 40' tightly against the stationary contact I2 and terminal 26. Y Sub- Asequent downward movement of handle 4I will tacting position, latch tip 52 of latch 50 engages the keeper 62 at the top of stationary contact element I2. Similarly when the handle @il and the movable assembly 25 are in the lower position, latch tip 53 of latch 5I engages the keeper 63 on the lower stationary contact I3. These latches thus prevent the handle assembly, in-

cluding the movable contact, from dropping down or being physically shocked out of engaged position and thus actually relieving the clamping pressure on the contact blades 40, 46. These latches also prevent the blade from being blown olic in case of excessively high current.

When, however, with the elements shown in Figure l, handle 4I is pulled down, pin 66 bears against dog leg 54 of latch 56 and rotates latch 56 counterclockwise to disengage latch tip 52 from keeper 62. Further downward movement of handle 4I brings the latch 5E) against the stop member 65 to prevent further movement of handle member 5I and bracket 43 around the pin so that the entire handle assembly now rotates counteiclockwise about the clamping screw 16 to release the clamping pressure on the bridging blades 40, 46.

Similarly, when the lower contact I3 is engaged, a lift of handle 4I will rst cause pin 60 to 'engage dog leg 55 of latch 5l to disengage latch tip 53 from keeper 63 and subsequent lifting of handle 4I causes lat-ch 5I to bear against the opposite side 'of member 65 so thatfurther lifting of handle 4I causes the handle assembly to rotate upwardly around the clamping screw 16 to release the clamping pressure on the bridgf ing blades 46, 6', central terminal block 26 and the lower terminal I3. The movement of the entire contact assembly 25 around pivots 33 and 34 is in addition to the movement of the plates move the contact plates 46, 40 down to the H neutral dotted Aline position shown in Figure 1. Still further downward movement of handle 4I will lbring the contact plates 40, 40' into registry with the lower stationary contact I3 and terminal 26. The final downward movement of handle 4I "will clamp thefcontact plates 40, 40 tightly against the lower Contact I3 and the terminal 26.

The entire clamping action is accomplished by A`a single clamping screw hereinafter described which screw will effect the clamping operation when it is turned clockwise with respect to Figure 1 when the switch handle 4I is raised; and counterclockwise with respect to Figure 1 as the switch handle 4I is lowered to the down position.'

The switch handle 4I is, as shown in Figure 2, secured in any suitable ymanner to the bracket 43, which bracket d3 is mounted for limited rotation on the pin 45 carried between the side members 46, 41 of the handle assembly. The side members 46, 41 are spaced from each other by the spacer piece 48 to which they are secured by rivets 49, 49.

hatches 50 and 5I are also rotatably mounted onpin 45 and are each provided with latch tip elements 52, 53 respectively and dog leg portions 54, 55 respectively. Dog leg portions 54, '55 of latches 5I] and 5I extend up on either side of pin r which is carried between the plates of bracket 43.

`When the handle 4I andthe entire movable contact assembly Y25-are raised to the 'upper'co'n- 456, 41 around the center of clamp operating screw 10 hereinafter described.

The back ends 'of plates 46 and 41 have mounted between them the projection 66 biased toward the right with respect to Figure 1 Eby the lcompression spring 61. Member previously described has an extension 68 provided with a hook 69 engaging pin 1I on projection 66.

. When the contact assembly 25 is in the neutral central position shown by dotted lines in l Figure 1, projection 66 is pressed .by the compression spring 61 into the notch 12 of the central extension 13 of the terminal 26, mounted on. the frontof panel II and thus maintains the entire movable contact 25 in neutral position.

When the handle 4I is lifted from the neutral position, the .pin 65 bears against dog leg 55 of .latch tip I5I which in turn pulls out member 65 thus pulling on extension 68 and hook 69, thereby pulling on pin 1I of projection 66 to disengage projection 66 from the notch 12.

As soon as projection 66 is disengaged from notch 12, further lifting of the handle moves the entire contact assembly 25 up. When the entire contact assembly reaches the up position with Vcontact .blades 4D, 4o" engaging the upper contact I2 and terminal 26, further upward movement of the assembly 25 rotates the clamping screw 1li thus clamping the blades 40, 4B tightly vagainst the upper contact I2 and the terminal 26 as hereinafter more fully described.

The 'same action occurs, of course, during down-v handle 4 I and its bracket 43 rotate-about pin 45 tov dls'engage either the latch 5I) or 5l 'depending on whether contact is made at the top or bottom;

or to disengage projection 66 should the contact assembly be in neutral position.` Second, thecontact assembly is then rotated-to" its next position about the 'centers 33 and 34.-`Thirdly, after either contacts I2 orl I3 have'been engaged, the handle assembly rotates about the screw 'I0 toclarnp the contact blades 4B, 45 against either ofthe stationary contacts I2 or I3 and terminal 26. Y'

The iirst and second centers offrotation (pin 45 and pivots 33 and 34) have already been de scribed both as to characteristics and operations. The operation of the third center of rotation (about screw I5) in order to clamp themovable contact blades 45 against either of the stationary contacts is shown more Aspecifically in connection with Figures 5, 6 and '7.

Figure 5 shows the position of the elements with the contact assembly in current carrying engagement iwith the upper stationary contact I2.

-Figure 6 shows the same assembly with the elements in the neutral or dotted line position of Figure 1. A I

Figure 7 shows the position of the elements with the movable contact-assembly vengaged with the lower stationary contact I3.

`Each of the pair of movable contact blades 40 and -40 is provided with a flexible metallic spring-like clamping plate '15, 'I5'. Theclarnp` ing nuts 'I6 and '55 bear against the clamping plates 'I5 and 'I5' in order to exert pressure on the blades 45 Land fifi'. Theclamping nuts 'I6 and I6 are adjusted and locked by set screws "I8, I8 registering and engaging some of the notches 19, I9 of each of the nuts 16,- 'I6; the seti screws being threaded into appropriate threaded openings in the clamping plates 15, 'I5'.

It should rst be pointed out that the clamping screw 'Ill is a right hand threaded screw and that this single screw is utilized to perform the clamping function at both the top and bottom position. The advantage of this type of construction lies in the fact that right hand threads are standard practice in the manufacture of screws and thus eliminates the necessity for a special machining operation requiring composite threading; and also the arrangement shown in Figures 5, 6 and 7 is such that for the first time a-- clamping action is accomplished by rotating an ordinary right-hand clamping screw in either a clockwise or counterclockwise direction. It will be understood, however, that a left-handed screw maybe used or a double'threaded screw atopposite ends .may be employed for direct action in place of the reaction on the nut.

The side members 46 and il are, in addition to their being riveted to the spacer block 48, further supported by reason'of the fact that the ridges 80 and SI in the side member 46 cooperate with a corresponding depression 82'in the spacer washer 83. Spacer washer'83 has a corresponding ridge 84 on its opposite side which cooperates with a groove Bein the blade 40.

The compression spring 90 surrounding the screw 'IU passes through an opening 9| in switch blade 4U and beyars at one end against the clamping plate 'I5 and at theopposite .end against the outer surface of handle plate4'I to :bias the assembly consisting of handle plates 4T and 46 with their associated elements aswellas the spacer Washer -83 to the right.

counterbore 8l of switchy Counterbore 'Illifn switcli 75 i ing nut 16 to bear opening 9 I in the 8l of handle plate 46 engages recess S2 of spacingv washer 83; and ridge 34 of spacing washer 33 engages the notch or recess 85 in the annular plane surface of counterbore 3'! of opening 9| of switch blade 40.

The handle plates 45 and Il are keyed to the clamping screw l5. `Clamping screw 'Ill is a substantially cylindrical member 'as shown having a squared portion 50c. Plates 46, 41 are provided with matching square openings receiving the squared portion 'Ice of the member I5. Clamping screw 'IU is provided with the threaded end '10a engaging the threads of nut 'I6 and the threaded end 75h engaging the threads of nut 'i When the movable contact assembly 25, including the handle plates 45 and 4I, has moved the blades 40 and 45 to the upper contacting position, the blades 4?, 4G and the clamping" plates I5, I5 can no longer move clockwise.v Thereafter further lifting of the handle 4I rotates the screw 'I0 in a clockwise direction, with respect to Figure 1.

This rotation about the center of screw 'ID occurs after the entire assembly has been rotated around the pivots 33 and 34 to the upper bridging position. This rotation now unwinds the threaded end 10b of clamping screw 'I6 from the righthand clamping nut 16', and turns the threaded end 'Illa into the left-hand clamping nut 16, Figure 5.

Since the clamping nuts 'I6 and 'IG' are pre vented from rotating by the set screws 18, I8', the entire handle assembly including handle plates 46 and 4l and the screw 'I5 will be moved axially to the left and cause the left-hand clamp `against the face of clamping plate 15.

rThis in turn draws the right-hand clamping washer which is captured in shouldered recess 96 in the right-hand end of the screw 1U, toward the left against the outer face of the rightu hand clamping plate 'I5'.

In this position the corresponding left-hand clamping washer 95 in recess 96 of left-hand end of the screw 'I0 is loose.

Thus, the further rotation of screw 'I5 above described will draw the clamping plates '15, I5 together to exert clamping pressure on blades 40, 40' and drive the blades into tight clamping engagement with contacts I2 and 26.

This pressure is obtained as shown by clamping nut 76 rmly engaging clamping plate 'I5 and by clamping washer 95 firmly engaging clamping plate 'I5'.

The reverse or opposite action of the above pro ycedure takes place when the handle assembly is by exerting clamping pressure on the switch` blades 4I), 4I.

The entire assembly is released and returns to neutral position as shown in Figure 6 on move ment of the switching members from the position of Figure 5 or the position of Figure '7 (the up or down positions) toward the central or neutralposition.

By means of the foregoing it will thus betseen 7 that ay single member having ordinary simply machined right-hand threads at, each end may readily be used to provide an effective clamp for a double throw knife blade type switch wherein the bridging or connecting blades are effectively clamped at both the upper and lower positions.`

In the foregoing I have described*r my invention solely in connection with a specific preferred embodiment thereof. Since many variations and modifications of my invention should now be obvious to those skilled in the art, I prefer to be bound not by the specific disclosure herein contained, but only by the appended claims.

I claim:

1. In a switch mechanism, a contact having two terminals, screw means, means for operating said contact to either of its terminals, said screw means thereafter clamping said contact into engagement with the terminal to which it has been operated?, said screw means being rotatable clockwise for eiecting clamping engagement with one of said terminals and rotatable counterclockwise forgeifecting clamping engagement with the other of said terminals, a nut and washer provided on opposite ends of said screw means, said screw means reacting on the nut on one end to produce a force in the opposite direction from the axial movement to said screw means and acting on the washer at theopposite end to produce a force in the same direction as the axial movement of said screw member.

2. In a switch mechanism, a contact having two terminals, a screw member, means for operating said contact to either of its terminals and means for thereafter clamping said contact into engagement withthe terminal to `which it has been operated, said screw member being rotatable clockwise for electing clamping4 engagement. with one of` said terminals and rotatable-counterclockwise for effecting clamping engagement with the other of said terminals, a nut and washer provided onopposite ends of said screw member, said screw member reacting on the nut on one end toproduce a-,force in the opposite direction. from the axial movement of said screw member and acting on a washer at the opposite end to produceA a. force in the same direction as the axial movement of said screw member, and said screw. member when the contact engages the. opposite terminal` acting. on the opposite nut to set up a force opposite to the axial movement of said screw member and acting onv the opposite wash.- er to produce a' force in the same direction as the direction of axial movement of. said screw member.

3.; In;a, clamp tight switcha pair of terminals,

said terminals and: operable counterclockwise to engage the other of said terminals, a screwmember rotatable clockwise by said bladewhen it is operated` to engage one of said terminals and counterclockwise with said switch blade when said switch blade is operated to engage the other of. said terminals, and means controlled by'saidscrew member for clamping said switch blade against the terminal with which it isv engaged, Said means includingy nuts on the ends of said screw member,` said screw member in one direction oft rota-f tion compressing the blade against the terminal through one of saidnuts, the direction of clamping, beingopposite to the direction of axial move.- ment of said screw member.

4. Irl-,a clamp tight switch, apair of terminals,v a switch blade operable clockwise-to engage4 one of said terminals and operable counterclockwise to: engage the other of said terminals, aA screw member rotatable clockwisev by said blade when` it is operated toeng-age one of said terminals and.`

clamping being opposite to the direction of axial.k

movement of said screw member, and the same direction of rotation of. said screw member causing the other end o1v said screw to directly com--y press the blade against the opposite sider of saidv terminal.

5.. A double throw switch comprising a first contact, a. second contact. a switch arm carrying a contact and having. a neutral position and mov# able in one direction to. engage said first contact and inl the opposite. direction to engage said second con-tact,y a screw member threaded atA both ends and having arst and second nut at opposite ends operable: whensaid switch arm is operated in either direction to clamp said arm against itsy engaged contact, said movable switch arm` being mounted in said screw member, said screw member being rotated in one direction, after said switch arm Contact engages said iirst contact and reacting on. said first nut at one end to compressY the contact in said switch arm against the firstl contact, the direction of clamping force being op positeto. the.- direction of axial movement of said screw member, the. same direction of rotation or"- said-screw. memberfcausing the.- other end of said Y screw to directly compress the movable contactv in. said switch'v arm against the first contact, theV forcefbeing, in the same direction as thev axial movement of the-screw member, said screw mern-` ber being rotated in: the opposite direction, after saidswitch arm contactengagessaid second con l tact, and'. reacting'` on said second nut at. the otherfend` to= compress the contact on said switch arm againstsaid second Contact, the direction ol. clamping force being opposite to the direction of axiaL movement of said screw member, thefsamef last mentioned direction of. rotation of said screw member: causingL the other end of' said screw member to directly compress the movable contact. in said-1 switch arms againstthe secondl conf tact, the forcebeing; in thesame direction as the axia-l'movement of the screw member.

OTTO JENSEN.

V a switch blade operable clockwise to. engage one of REFERENCES CITED The followingv references are of record. in4 the..-

file of this patent:v

UNITED STATES PATENTS OTHER l REFERENCES.

TheAutomatic Reclosingf Breaker. Co., Bulletin 

